The present invention relates to certain bicyclic amide ketals and derivatives thereof, which have been found to be useful additives for inclusion in functional fluids particularly hydraulic fluids as acid and water scavengers. The present invention also includes as one embodiment thereof certain of these bicyclic amide ketals containing hetero atom functionality that were previously known.
In U.S. Pat. No. 4,277,354 to Brois et al., certain oil-soluble 2- and/or 8-alkyl-substituted 1-aza-3,7-dioxabicyclo[3.3.0]oct-5-yl methyl alcohols are disclosed that have particular utility as additives to functional fluids to prevent corrosion of copper. Ester derivatives thereof of related structure are disclosed in U.S. Pat. No. 4,017,406. Further alkylene glycol esters of these compounds are disclosed in U.S. Pat. No. 4,199,463.
In U.S. Pat. No. 3,600,214 to Feinauer et al., certain 5-alkyl- or 5-aryl-4,6-dioxa-1-azabicyclo[3.3.0]octanes having utility as dyeing aids for synthetic fibers are disclosed.
Functional fluids are often exposed to extreme operating conditions. Such fluids may have to withstand elevated temperatures or be subjected to alternating extremes of high and low temperatures while maintaining desirable fluid properties. In addition, many fluids are exposed to sources of chemical contamination. Especially detrimental may be acid contaminants and water, either of which may seriously degrade fluid performance or affect additional components in the fluid system causing corrosion or degradation of system parts and ultimately contribute to a failure of the fluid system. Even where structural failure may not be a problem, contamination may still be undesirable. For example, in a dielectric fluid, small quantities of water on the order of only a few parts per thousand may seriously degrade the fluids dielectric properties.
Accordingly, it is well-recognized that nonaqueous functional fluids may require the presence of additives to modify or control the effects of contaminants, particularly water and acids, therein. Although numerous additives are currently known and employed, a continued need exists to provide new additives that are compatible with many varieties of fluids or to provide improved protection under various operating conditions.